A man faces a number of charges for pretending to be Justin Bieber to lure young girls to perform sex acts and pose topless for him on the Internet.

Christopher Patrick Gunn, 31, has been charged with sexual exploitation and child pornography for using Facebook to connect with girls and convince them to expose themselves through pictures and videos.

The man from Montgomery, Alabama threatened the girls that he would publish the image of them online to destroy their reputations if they didn’t perform sex acts he wanted to see, according to authorities.

Accused: Christopher Patrick Gunn, 31, has been charged with posing as Justin Bieber and convincing young girls to perform sexually explicit acts

In a federal grand jury indictment on Thursday, it was revealed that the fake Justin Bieber convinced girls ranging in age from nine to 16 to perform acts.

He contacted girls from at least six other states, including Florida, Virginia and California, according to federal authorities.

He was charged this week with 10 counts of sexual exploitation, three counts of interstate extortion and three counts of using an interstate commerce in furtherance of unlawful activity.

Gunn was previously charged during his initial arrest in March with two counts of child pornography.

This came after three girls, ages 12 and 13, from Biloxi, Mississippi told police that Gunn had tricked them into performing the acts.

Gunn promised the girls free tickets to the pop star’s concerts and backstage passes, according to police.

He would tell girls he was Mr Bieber to persuade them to take their tops off, authorities said.

Once they did, he demanded that they do more explicit activities.

If the girls refused to do so, he would scare the girls into believing that he would publish their behavior.

Donnie Dobbs, a Biloxi police detective, told the Sun Herald that girls in at least two other neighbouring cities also reported Gunn.

‘They didn’t want to play his game anymore,’ Detective Dobbs told the newspaper of the girls who tipped off the Biloxi police.

For years, Gunn targeted young girls online, authorities said.

From 2009 until summer 2011, Gunn contacted girls online pretending to be a new kid in town.

He started to pose as Mr Bieber in November, police said.

Gunn has been serving a three-year probation sentence in a Florida case, where he was convicted of felony charges of grand theft, burglary and other crimes.

The new charges against Gunn as a Bieber poser comes after New Jersey authorities arrested a Canadian man earlier this month for posing as the teen singer.

Another ‘imposter': Lee Moir, of Canada, was also charged with posing as Justin Bieber to lure young girls into performing sex acts online in April

Lee Moir, 34, of Toronto, Ontario, created a Facebook account claiming he was the starto get young girls to perform sex acts online.

One of the victims was a 12-year-old girl in New Jersey, who said Moir talked her into a sexually explicit video chat.

The victim quickly realised that she was not talking to Bieber at all and tried to sever contact with Moir, who then allegedly threatened to harm her family and post the videos on pornographic websites.

Moir was arrested on April 4 after an undercover Canadian officer posed as a 14-year-old girl online.

Authorities said he engaged the officer in sexual conversations and requested a meeting and was arrested at that location.